The conventional approach to cooling of card-mounted electronic components is to use solid metal thermal mounting plates which conduct the heat dissipated by the components to a heat sink disposed at an edge of each plate. Such an approach results in high thermal gradients and high component temperatures, especially for those components which dissipate high power.
Heat pipes have been proposed for cooling individual electronic components. (See, for example, the article "Transient Thermal Impedance Of A Water Heat Pipe," by S. W. Kessler, Jr., and presented at the ASME Winter Annual Meeting, Washington D.C., Nov. 28 through Dec. 2, 1971.) However, the prior art heat pipes use the same wicks for fluid transport as for heat transfer, requiring a compromise between the overall thermal conductance of the heat pipe and the heat transfer capacity; furthermore, they were not of a configuration which was readily adaptable to the cooling of components mounted on circuit cards.